Swift catches the changing-look AGN NGC 1566 in an X-ray outburst again
ATel #12826; Dirk Grupe, Rebecca Mikula (Morehead State University), S. Komossa (MPIfR), Christopher Kochanek, K. Z. Stanek (OSU), Ben Shappee, Anna Payne, James Armstrong (IfA Hawaii), Katie Auchettl (DARK), Norbert Schartel, Michael Parker (ESAC), Xinyu Dai (U. Oklahoma)
on 31 May 2019; 20:00 UT
Credential Certification: Dirk Grupe (dgrupe007@gmail.com)
Subjects: Optical, Ultra-Violet, X-ray, AGN
We report on a dramatic re-brightening in X-rays of the changing-look
Seyfert galaxy NGC 1566 by Swift. NGC 1566 has repeatedly changed its Seyfert type in the past. After the INTEGRAL detection of a hard
X-ray outburst in June 2018 (Ducci et al., ATel #11754) with associated
dramatic increases in the soft X-ray and UV fluxes (Ferrigno et al., ATel #11783;
Kuin et al., ATel #11786; Grupe et al., ATel #11903) we started monitoring
NGC 1566 with Swift on a weekly cadence. We found that the 0.3-10 keV X-ray flux
on 2019-05-28 22:45 UT of 6 x 10^-14 W/m^2 was a factor of 10 brighter than the
Swift XRT observation one week earlier. This dramatic increase in the
X-ray flux was confirmed in our next observation on 2019-05-29 01:50 UT,
when its flux was 7.4x10^-14 W/m^2.
The Swift UVOT Vega magnitudes on May 29 were V = 13.86/13.83, B = 14.44/14.41,
U = 14.06/14.02, UVW1 = 14.17/14.12, UVM2 = 14.53/14.46, and UVW2 = 14.64/14.58,
uncorrected/corrected for Galactic extinction. These were determined with a 3"
source extraction radius to avoid significant contribution by starlight and
have an uncertainty of 0.05 magnitudes. The observed magnitudes from the May 21st
observation were: V = 13.93, B = 14.80, U = 14.46, UVW1 = 14.72, UVM2 = 14.93, and UVW2 = 15.16.
We are now monitoring this AGN with Swift on a daily basis.
We would like to thank Brad Cenko for approving our ToO requests and the Swift team
for executing our observations.
